Laura Fogt
EEES 4730
Outline
 Objective
 Background information
 Problem and causes
 Consequences to aquatic systems
 Solutions
 Research publication
Objective
 To discuss the ecological impacts of aquatic invasive
species and propose some possible solutions.
Invasive Species
 Definition
 Where they are found
 In and around bodies of water
http://www.invasivespeciesinfo.gov/aquatics/main.shtml
Problem
 Thousands of aquatic species have been dispersed or
transplanted across the globe through human
interaction
Causes
 Humans have played dominant role in species
transport across the globe through man-made
pathways
 Intentional

Ex: intended movement of living seeds, whole plants or pets
 Unintentional

Ex: ballast water discharge
Ballast Water Discharge
http://www.eoearth.org/article/Aquatic_invasive_species
Other methods of transport
 Ships and boats
 Organisms attach themselves to hulls of vessels
 Canal construction
 Intentional release
 Food sources
 Sport fishing

7 out of the 8 fish on the “One Hundred of the World’s Worst
Invasive Alien Species” were introduced for sport (Cambray, 2003)
More methods
 Shipping
 Oyster transfer considered the primary vector for the spread
of invasive macroalgae in the Mediterranean (Roman, 2010)
 Algal packing material used for shipping live seafood and bait
may contain juvenile crabs, snails, mussels, and other
organisms often discarded near shore(Roman, 2010)
 Aquaculture
 In one single incident in 2000, the population of salmon in
Maine was elevated by 1000 times when approximately
100,000 fish escaped (Anonymous, 2011)
 Ornamental fish trade
Consequences
 Ecological changes
 Extinctions through competitive exclusion

1/3 of endangered and threatened species in US are listed, in part, due to
the action of invasive species (Cambray, 2003)
 Trophic alterations (predation, competition, food web alteration)
 Threat to aquatic biodiversity conservation



Biotic homogenization
Zoogeographic pollution
Hybridization and introgression


Occurs among fish species due to introductions for sport or commercial
fishing, biological control, or through accidental introductions of bait
species (Rhymer et al, 1996)
The average similarity of fish faunas among the US has increased by 7.2%
(Rahel, 2007)
 Diseases and parasites
 Habitat and spatial alterations
Solutions
 Strict penalties for violations
 More than 50 national and international laws and regulations are in
place to restrict the transport of nonnative species. Few of these
carry stiff penalties for noncompliance (Roman, 2010)
 Ballast-water exchange
 1996 National Invasive Species Act following Zebra mussel spread in
Great Lakes
 Voluntary in many coastal areas
Solutions
 Follow guidelines
 Aquatic Nuisance Species Handbook
 Identification and control of invasive species in Michigan
 Northeast Aquatic Nuisance Species Panel website (NEANS)
 Gives mechanical, chemical and biological methods to control each aquatic
invasive species
 Prevention is the best way to deal with invasive species
rather than eradication
 Prohibitive legislation (Lacey Act in US)
 Prohibits trade in wildlife, fish, and plants that have been illegally taken,
possessed, transported or sold
 Regulation of high risk activities such as ballast water transfer
 Education
Research
 Impacts of alien invasive species on freshwater fauna at
risk in Canada
 Alan Dextrase and Nicholas Mandrak, 2003
 Examines threat factors contributing to the
endangerment of freshwater fishes and molluscs in
Canada and the nature of alien invasive species
introductions affecting aquatic species at risk
Background
 In Canada, species have been assigned status
designations since 1978 by the Committee on the
Status of Species at Risk in Canada (COSEWIC)
 Status designations

Extinct, Extirpated, Endangered, Threatened, Special Concern
 COSEWIC meets regularly to assign status
designations at risk using status reports that
summarize biological information, population and
habitat trends, limiting factors and threats
Background
 Freshwater fish fauna of Canada consists of 230
species, including 23 alien species.
 34% of native species designated at risk
 Freshwater molluscan fauna consists of 180 species,
including 12 alien species
 7% of native species designated at risk
Area of study
Materials and Methods
 Threat factors compiled for each Canadian freshwater fish and
mollusc species designated Extinct, Extirpated, Endangered or
Threatened by COSEWIC
 Special concern excluded from analysis because they are not
immediately imperilled and threat factors are often poorly
understood
 Threats that occurred in the past, are currently occurring, and
expected to occur all considered in analysis
 Threats assigned to various categories identified by the World
Conservation Union
 Threats sub-divided into two groups and classified as primary or
secondary
 The vector of introduction was determined when alien invasive
species were a factor contributing to decline or endangerment
Fish Results
 42 taxa of freshwater fishes reviewed
 Alien invasive species was second only to habitat loss
as a threat factor
 Threat factor for 26 out of 41 taxa, 63%
 Primary factor for 14 out of the 26
 Primary factor in 4 out of 5 extinctions
Threat factors identified in COSEWIC status reports for freshwater fishes at risk
Mollusc Results
 Alien invasive species cited as primary threat factor for
6 of 11 species (55%)
 All cases due to impacts of zebra mussels
 All result of ballast water discharge
Common name
Lake Winnipeg physa
Banff Springs snail
hotwater physa
dwarf wedgemussel
northern riffleshell
snuffbox
wavy-rayed lampmussel
round hickorynut
kidneyshell
mudpuppy mussel
rayed bean
COSEWIC
status
Threat factor
Endangered
Endangered
Endangered
Extirpated
Endangered
Endangered
Endangered
Endangered
Endangered
Endangered
Endangered
Changes
Invasive
in native
Habitat loss/ alien
species
Human
degredation species Pollution dynamics disturbance
P
P
P
S
P
P
P
P
P
P
P
S
P
P
P
S
P
P
P
S
S
P
P
P
S
P
P
P
S
P
P
P
S
P
P
Threat factors identified in COSEWIC status reports for
freshwater molluscs at risk in Canada
Vectors-Freshwater Fish
 Seven different pathways
 65% related to sport fishing
 Also introduced through ballast discharge, aquarium
fish releases, canals, movement of recreational boats,
aquaculture and horticulture escapes
 Of the 17 species introductions related to sport fishing,
only 2 authorized
Discussion
 In >75% of cases, listed species face multiple threat
factors
 Largest numbers of listed fishes in Great LakesWestern St. Lawrence and Pacific Islands Ecological
areas.
 Highest native species richness
 Highest human impact
Solutions
 Species at Risk Act in 2003
 Enacted to prevent extinction of Canadian wildlife
species


Provides legal protection to listed species and their habitats
Mandate development of recovery strategies within specified
time frames
References
 Anonymous. 2011. Accessed online from http://see-thesea.org/topics/species/invasive_species.htm. on October 30, 2011
 Cambray, J. 2003. Impact on indigenous species biodiversity caused by the
globalization of alien recreational freshwater fisheries. Hydrobiologia. 500: 217230
 Dextrase, A. and N. Mandrak. 2004. Impacts of alien invasive species on
freshwater fauna at risk in canada. Biological invasions. 8: 13-24
 Northeast Aquatic Nuisance Species Panel, 2011. Accessed online
http://www.northeastans.org on October 30, 2011.
 Rahel, F. 2007. Biogeographic barriers, connectivity and homogenization of
freshwater faunas: it’s a small world after all. Freshwater biology. 52: pp 696-710
 Rhymer, J. and Simberloff, D. 1996. Extinction by hybridization and
introgression. Ecology, evolution, and systematics. 27: 83-109. Referenced from
http://www.annualreviews.org/doi/pdf/10.1146/annurev.ecolsys.27.1.83.
Accessed on October 29, 2011.
 Roman, J. 2010. Aquatic invasive species. The encyclopedia of earth. Accessed
from http://www.eoearth.org/article/Aquatic_invasive_species on October 30,
2011.